root / synthbench / euroben-dm / mod2i / .svn / text-base / d_merge.f.svn-base @ 0:839f52ef7657
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Subroutine d_merge( np, nodes, mx, keys, irnkl, itabl, itabr ) |
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! -------------------------------------------------------------------- |
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Use numerics |
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Implicit None |
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|
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Integer :: np, nodes, mx, irnkl(np), itabl(nodes+1), |
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& itabr(nodes) |
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Real(l_) :: keys(mx) |
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|
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Real(l_) :: ik, itabk(nodes) |
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Integer :: i, j, k, il, ir, ij, irnkj(nodes), jprocs |
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Real(l_) :: w(np) |
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! -------------------------------------------------------------------- |
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! Make sure that the indicies have base 1. |
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|
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If ( itabl(1) /= 1) Then |
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Do i = nodes+1, 1, -1 |
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itabl(i) = itabl(i) - itabl(1) + 1 |
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End Do |
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End If |
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|
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Do i = 1, nodes |
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itabr(i) = itabl(i+1) - 1 |
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End Do |
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|
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Do j = 1,nodes |
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itabk(j) = keys(itabl(j)) |
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irnkj(j) = j |
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End Do |
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! -------------------------------------------------------------------- |
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! Check for empty segments and remove them. |
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|
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jprocs = nodes |
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i = 1 |
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Do j = 1, nodes |
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If ( itabl(irnkj(i)) > itabr(irnkj(i))) Then |
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jprocs = jprocs - 1 |
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Do k = i, jprocs |
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irnkj(k) = irnkj(k+1) |
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End Do |
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Else |
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i = i + 1 |
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End If |
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End Do |
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! -------------------------------------------------------------------- |
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! Sort the proc-way merging table: |
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|
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Do j = 2, jprocs |
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|
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! --- Consider each of the original elements in turn. |
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|
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ij = irnkj(j) |
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ik = itabk(ij) |
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|
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! --- and look for a place to insert it. |
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! The slot "j" is now empty. |
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|
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Do i = j-1, 1, -1 |
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If ( itabk(irnkj(i)) <= ik ) Go To 10 |
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irnkj(i+1) = irnkj(i) |
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End Do |
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i = 0 |
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10 Continue |
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irnkj(i+1) = ij |
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End Do |
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! -------------------------------------------------------------------- |
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! The merging table is now in sorted order. |
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! proceed with the merge. |
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|
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Do i = 1, np |
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|
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! --- Remove the smallest element from the merging list. |
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ij = irnkj(1) |
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|
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! --- Refresh the merge table. |
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|
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il = itabl(ij) + 1 |
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ir = itabr(ij) |
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ik = keys(il) |
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itabk(ij) = ik |
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itabl(ij) = il |
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irnkl(il-1) = i |
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|
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! --- Pick out each element in turn; The first slot is now empty. |
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|
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If ( ir >= il ) Then ! --- Look for slot to insert new data. |
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Do j = 1, jprocs-1 |
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If ( itabk(irnkj(j+1)) >= ik ) Go To 20 |
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irnkj(j) = irnkj(j+1) |
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End Do |
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j = jprocs |
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20 Continue |
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irnkj(j) = ij |
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Else ! --- Retire a slot |
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jprocs = jprocs-1 |
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Do j = 1, jprocs |
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irnkj(j) = irnkj(j+1) |
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End Do |
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End If |
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End Do |
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Do i = 1, np |
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w(irnkl(i)) = keys(i) |
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End Do |
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keys(1:np) = w(1:np) |
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! -------------------------------------------------------------------- |
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End Subroutine d_merge |